R Basics

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Problem 1:

  1. From set = {1.5, 15, 0, 54, 23}, pick two numbers and perform the Following Operations:

.Subtraction .Multiplication .square root

#Subtraction 
15-1.5
## [1] 13.5
#Multiplication 
23*54
## [1] 1242
#Square R
sqrt(15)
## [1] 3.872983

Problem 2

Suppose you have a set of numbers representing the assignments scores:

scores <- c(87,100, 91, 95, 81.5, 0, 39, 74, 92)

#Calculate the average of the scores, and round your answer to two decimal number
mean(scores)
## [1] 73.27778
#Find the Maximum and Minimum score
min(scores)
## [1] 0
max(scores)
## [1] 100
#Find how many scores were above the average, use coding for this
scores[scores>mean(scores)]
## [1]  87.0 100.0  91.0  95.0  81.5  74.0  92.0
#Create a new set called new_scores that includes the elements from indices 2 to 6 of the scores vector
new_scores <-scores [2:6]

Problem 3:

Read section 2.3, then answer the following questions

# Create a vector with the number 1 repeated 5 times. Print it
number_one <- c(1,1,1,1,1)
print(number_one)
## [1] 1 1 1 1 1
# Create a vector with a sequence of numbers from 1 to 10 with a step of 2. Print it
sv <- seq(1,10, 2) 
print(sv)
## [1] 1 3 5 7 9
# Create a vector by repeating a sequence from 1 to 3, 2 times. Print it.
rv <- rep(1,3, 2)
print(rv)
## [1] 1 1

Problem 4

mixed_vector <- c(1, "two", 3.0, TRUE, 2)

# Check the class of the vector
class(mixed_vector)
## [1] "character"
## Coerce to numeric and print it 
as.numeric(mixed_vector)
## Warning: NAs introduced by coercion
## [1]  1 NA  3 NA  2
print(as.numeric(mixed_vector))
## Warning in print(as.numeric(mixed_vector)): NAs introduced by coercion
## [1]  1 NA  3 NA  2